'99 XLT shift points off

[Petey]

I recently rebuilt the 5R55E for my 99 XLT. New torque converter, gaskets, filter and fluid. Had it looked over when it was on the table by a pro and he also put it back together with the aid of a manual. After putting it back in the vehicle and driving it for about 10 miles, the O/D light started to flash (which also makes it impossible to turn overdrive off). I have to let off the gas for either the 1-2 shift or the 2-3 shift (I can't quite tell, takes place at about 20-25 MPH (assume 2-3 shift)). Also, during the next upshift from that one, the RPMs do not change but the speed continues to climb. I blew out the valve body gasket months before but knowing that I was going to have to replace or rebuild the tranny, I kept driving it til it would go no more. Having driven it for a couple of months in this state (average commute of 40 miles one way, mostly city freeways), is it possible that the computer learned new shift points being that this tranny is computer controlled? If this is the case, is there a simple way to reset the factory shift points or do I need to take it in and have them reprogrammed. Also any other thoughts or ideas would be greatly appreciated. Thanks.

 

[Blee1099]

Sounds like the torque converter isn't locking up. I would have the your truck scanned for codes since you had the O/D light flash.

 

[Petey]

What would cause this. It has fresh fluid and a new converter. Also, if I try hard, I can keep the light from coming on until I have to slow down for a light or a stop sign.

 

[Blee1099]

It could be a number of things.. The torque converter and flex plate might not be properly aligned. The flex plate might have cracks or worn teeth. There is so many things that could cause your problems. I suggest going to the place you had it rebuilt at or if you did it yourself, take it somewhere reputable to go over everything.

 

[Petey]

Would that have an affect only during shifts? It goes down the road just fine at street and highway speeds. Only has a problem during 2-3 shift